A steam turbine system includes a rotor shaft that is axially supported by a thrust bearing. During rotation of the rotor shaft, an axial force is exerted by the rotor shaft on the thrust bearing. When the axial force exceeds a predetermined force for an extended period of time, the thrust bearing can become degraded.
The steam turbine system detects when the thrust bearing becomes degraded by measuring an axial gap between the thrust bearing and a portion of the rotor shaft. When the axial gap between the thrust bearing and the portion of the rotor shaft is less than a predetermined distance, the system determines the thrust bearing is degraded. A disadvantage of this detection technique, is that no corrective action is taken to prevent degradation of the thrust bearing. Instead, the technique only detects degradation  of the thrust bearing after it has occurred.
Accordingly, there is a need for a system that can prevent degradation of a thrust bearing, due to excessive axial force loading, before the degradation occurs.